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Dynamic secretion changes in the salt glands of the mangrove tree species A vicennia officinalis in response to a changing saline environment
Author(s) -
TAN WEEKEE,
LIN QINGSONG,
LIM TITMENG,
KUMAR PRAKASH,
LOH CHIANGSHIONG
Publication year - 2013
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12068
Subject(s) - salt gland , halophyte , avicennia marina , secretion , biology , mangrove , epidermis (zoology) , osmoregulation , salinity , intertidal zone , salt (chemistry) , aquaporin , botany , ecology , microbiology and biotechnology , chemistry , anatomy , endocrinology
The specialized salt glands on the epidermis of halophytic plants secrete excess salts from tissues by a mechanism that is poorly understood. We examined the salt glands as putative salt and water bi‐regulatory units that can respond swiftly to altering environmental cues. The tropical mangrove tree species ( A vicennia officinalis ) is able to grow under fluctuating salinities (0.7–50.0 dS m −1 ) at intertidal zones, and its salt glands offer an excellent platform to investigate their dynamic responses under rapidly changing salinities. Utilizing a novel epidermal peel system, secretion profiles of hundreds of individual salt glands examined revealed that these glands could secrete when exposed to varying salinities. Notably, rhythmic fluctuations observed in secretion rates were reversibly inhibited by water channel (aquaporin) blocker, and two aquaporin genes ( PIP and TIP ) preferentially expressed in the salt gland cells were rapidly induced in response to increasing salt concentration. We propose that aquaporins are involved and contribute to the re‐absorption of water during salt removal in A vicennia officinalis salt glands. This constitutes an adaptive feature that contributes to salt balance of trees growing in saline environments where freshwater availability is limited.